Nutrigrow Vs. S-Chelate Comparison #1

I want to compare S-Chelate 12 Star with Nutrigrow fertilisers for use in continuous feed or fertigation (fertiliser in irrigation) systems like wicking pots and hydroponic systems.

Tomatoes Planted in Quadgrows – support strings still to tie up.

Most fertilisers sold for fertigation, whether powder or liquid, come in two or sometimes three parts. These powder fertilisers, which are much easier to store and economical to deliver, have to be made up into stock solutions which are then mixed together with water to form the final nutrient solution.

The reason for the two parts is they rely on Calcinit or similar to provide the needed calcium but when this is mixed with phosphorus (the P in NPK) calcium forms insoluble salts that the plant cannot utilise. By only mixing in dilute form, this reaction is minimised.

Nutrigrow is one of the two-part solutions and over the years I’ve found it very effective for my tomatoes. I realised that S-Chelate 12 Star was able to provide a similar level of nutrients, including calcium in a single powder. The reason 12 Star does not need premixing is the chelation technology used keeps the calcium in bio-available solution when mixed.

It’s a lot easier to just add a scoopful from the screw-top tub to a watering can than measure out 30ml of solution A and 30ml of solution B to add. Takes up a lot less room in the greenhouse, too.

Theory vs practice

The theory seems right and I can’t see any reason why 12 Star shouldn’t do the job just as well as Nutrigrow. In fact I expect it to be better for the plants. But theory is great until it meets the real world. I know 12 Star is a very good fertiliser from the its effect on other plants but this comparison should demonstrate its value for fertigation.

Comparative Plants

‘Hairy’ Tomato Stem – planting out up to the seed leaves to generate additional root growth.

I chose tomatoes because they’re what home growers most commonly grow in Quadgrows and hydroponic systems. They’re easy to compare as well, just weigh the tomatoes as harvested and note the numbers. Each Quadgrow had two Ailsa Craig, a Crimson Plum and a Black Cherry. They were all sown at the same time and grown the same way in the same compost in pots in the Vitopod.

I was very careful to match the plants in pairs so each Quadgrow’s plants are equal. The same multi-purpose compost, Bloom & Grow, was used in all pots. So no difference there.

Normally when I plant tomatoes on, I plant deep. The couple of inches of buried stem will respond by producing more roots. The more roots, the more nutrients the plant can take up and the better the eventual crop.

Feed & Water

The compost should provide enough nutrients for 4 weeks so I won’t be feeding at all until the second week of May. Each Quadgrow had 25 litres of water added to the reservoir and 10 litres watered onto the pots to settle the compost. I’ll top up as needed.